Method for placement of neuromonitoring needles

ABSTRACT

A neuromonitoring needle electrode placement gun which includes a housing, at least a first needle electrode and housing assembly, an elongated channel dimensioned and configured for accommodating axial movement of the at least a first needle electrode and housing assembly within the channel and for directing movement of the at least a first needle electrode and housing assembly and a pusher dimensioned and configured for engaging the at least a first needle electrode and housing assembly and for axially displacing the at least a first needle electrode and housing assembly.

RELATED APPLICATIONS

This application is a division of United States patent applicationentitled NEUROMONITORING NEEDLE-CARTRIDGE GUN SYSTEM having anapplication Ser. No. 14/176,109, a filing date of Feb. 9, 2014 and whichmatured into U.S. Pat. No. 9,782,200 on Oct. 10, 2017.

TECHNICAL FIELD

Intraoperative neurophysiological monitoring (IONM) is a real-timeassessment of neurological function involving the brain, spinal cord andrelated nerve structures. IONM facilitates the surgical process andreduces surgical risk by enabling a neurotechnologist (NT) to alert thesurgeon if and when spinal cord or neural structure compromise appearsimminent. Neuromonitoring is used for spine surgeries, as well as othertypes of surgical procedures such as craniotomies, total hip replacementand vascular procedures. The purpose of IONM is to reduce the risk tothe patient of iatrogenic damage to the nervous system, and/or toprovide functional guidance to the surgeon and anesthesiologist. IONMtechniques have significantly reduced the rates of morbidity andmortality without introducing additional risks. By doing so, IONMtechniques reduce health care costs,

To accomplish these objectives, a member of the surgical team withspecial training in neurophysiology obtains triggered and spontaneouselectrophysiologic signals from the patient periodically or continuouslythroughout the course of the operation. Patients who benefit fromneuromonitoring are those undergoing operations involving the nervoussystem or which pose risk to its anatomic or physiologic integrity. Ingeneral, a trained neurophysiologist attaches a computer system to thepatient using stimulating and recording electrodes. Interactive softwarerunning on the system carries out two tasks:

1. Selective activation of stimulating electrodes with appropriatetiming, and

2. Processing and displaying of the electrophysiologic signals as theyare picked up by the recording electrodes.

IONM records impulses generated by electrical stimulation of peripheralnerves and dermatomes. Using the International EEG 10-20 electrodeplacement system, cortical needle electrodes are precisely placedsubcutaneously to record sensory responses at specific locationsassociated with the spinal column and along the course of relatedperipheral nerves.

Data generated by intraoperative neurophysiological monitoring (IONM)provides a measurement of latency (time it takes for a nerve impulse totravel from a specific point of stimulation to a specific recordingsite), amplitude (strength of that impulse), and wave form definition.These recordings are called somatosensory and dermatome evokedpotentials.

Needle electrodes are inserted into associated muscle groups to monitorspontaneous and electrically evoked myogenic activity. Moreparticularly, in a typical procedure the neurotechnologist (NT) appliesmultiple stimulating surface electrodes in the pre-operative holdingarea. Sterile sub-dermal and intramuscular needle electrodes areinserted after induction and approval of the anesthesiologist. Thisprocess is done such that preparation of the patient continuesunimpeded. The type of surgery will dictate the number of attachedelectrodes, which can vary significantly from 15 to 60.

The present invention is generally directed to a system for applyingneuromonitoring needles to a patient and the means to connect tomonitoring equipment.

BACKGROUND OF THE INVENTION

Intraoperative Neuromonitoring is used during surgery in or near thecentral or peripheral nervous system. It provides a valuable tool forassessing the integrity of certain neurologic pathways/tracts of apatient during surgery. Such monitoring helps in early identification ofadverse events intraoperatively as well as providing a valuable tool forassessing the integrity of certain neurologic pathways/tracts of apatient during surgery. The monitoring typically requires placement of16-32 subdermal needle electrodes in a patient.

Patients benefit from neuromonitoring during certain surgicalprocedures, namely any surgery where there is risk to the nervoussystem. Most neuromonitoring is utilized by spine surgeons orneurosurgeons, but vascular, orthopedic, otolarygologists and urologysurgeons have all utilized neuromonitoring as well.

Neuromonitoring utilizes subdermal needle electrodes that are shallowlyplaced in the patient. The needles remain in place during surgery andare removed after the operation. Patients are often repositioned fortransport or other reasons while needles are still in place.

Needle tips can reemerge during moving, repositioning, and handling ofthe patient. Needle sticks, are a general problem in such procedures.There are an estimated 3.5 million needle sticks worldwide annually. Thecost for remediation of each needle stick injury is estimated to beabout $2,500. The Needle stick Safety and Prevention Act signed into lawon Nov. 6, 2000 revised the Occupational Safety and HealthAdministration's (OSHA) standard regulating occupational exposure toblood borne pathogens, including the human immunodeficiency virus, thehepatitis B virus, and the hepatitis C virus.

From the above, it is therefore seen that there exists a need in the artto overcome the deficiencies and limitations described herein and above.

SUMMARY OF THE INVENTION

It is an object of the present invention to minimize the risk of needlesticks during implant in the patient, during implant in the patient andwithdrawal from the patient.

It is another object of the present invention to more rapidly andprecisely implant neuromonitoring needles.

It is yet another object of the present invention to eliminate many ofthe conventional additional materials and procedures for securingneedles to the patient.

It is a still further object of the present invention to assure safetyand ease of needle disposal after withdrawal from the patient byautomatically providing structure to minimize human exposure to theneedles after withdrawal.

It is still another object of the present invention to provide acomplete integrated needle delivery system for use at an operating sitethat is ready to function without additional preparation other thanremoving the system from a single sterile package.

Additional features and advantages are realized through the techniquesof the present invention. Other embodiments and aspects of the inventionare described in detail herein and are considered a part of the claimedinvention.

The recitation herein of desirable objects which are met by variousembodiments of the present invention is not meant to imply or suggestthat any or all of these objects are present as essential features,either individually or collectively, in the most general embodiment ofthe present invention or in any of its more specific embodiments.

It has now been found that one form of the present invention includes aneuromonitoring needle electrode placement gun which includes a housing,an elongated channel having an axis and an axial extremity which is adischarge end, the elongated channel has an interior dimensioned andconfigured for receiving a plurality of associated needle electrodecartridges. Each includes at least one needle electrode having anexposed point and the plurality of associated needle electrodecartridges are each disposed at axially successive positions along theaxis within the elongated channel with each of the exposed pointsextending toward the discharge end. The elongated channel is carried bythe housing and a trigger is mounted for pivotal movement on the housingand a pusher cooperates with the trigger. The pusher is dimensioned andconfigured for engaging an associated needle electrode cartridge withinthe plurality of associated needle electrode cartridges that is nearestto the discharge end.

In one embodiment the neuromonitoring needle electrode placement gunfurther includes a cassette having a plurality of shelves carried by thehousing. The shelves are dimensioned and configured for receivingassociated coils of wire attached respectively to each of the needleelectrode cartridges.

Other forms of the present invention further include a cartridge forcooperation with an associated neuromonitoring needle electrodeplacement gun which includes a housing; at least one elongated needleelectrode, having an axial extent and having a pointed axial extremity,carried by the housing as well as at least a first generally planar winghaving first and second faces thereof. The first generally planar wingis carried by the housing in some embodiments.

Some embodiments of the cartridge further include at least a firstgenerally planar wing that is coated with a releasable adhesive on afirst face thereof. The cartridge may have engagement surfaces disposedon opposed sides thereof, the engagement surfaces may be dimensioned andconfigured for cooperation with an elongated track in the associatedneuromonitoring needle electrode placement gun. Each cartridge mayfurther include a wire fixed to the at least one needle electrode forconducting either a stimulus for a patient or a patient's response to astimulus. Each needle electrode may have insulation surrounding an axialportion of the axial extent of the at least one elongated needleelectrode and insulation may surround an axial portion of the axialextent of the at least one elongated needle electrode that is spaced apredetermined distance from the pointed axial extremity. The cartridgemay further include a second elongated needle electrode having an axialextent and having a pointed axial extremity carried by the housing andthe first and second elongated needle electrodes may be disposed incoplanar relationship. In addition the first and second elongated needleelectrodes may have the respective pointed axial extremities thereofdisposed in perpendicular relationship to and abutting a virtual linethat is coplanar with the first and second elongated needle electrodes.

The first and second elongated needle electrodes in some embodiments arespaced apart a distance corresponding to a distance suitable for adifferential amplifier to obtain an optimal response from the needleelectrodes. In some embodiments both needles in a given pair may measurespontaneous myogenic activity. In other embodiments one needle in agiven pair may provide a stimulus and the other needle in the pair maybe used to measure evoked myogenic activity. The respective engagementsurfaces may be dimensioned and configured for engagement withassociated elongated channels in an associated neuromonitoring needleplacement gun. Each cartridge may further include a second generallyplanar wing having first and second faces, the second generally planarwing may also be carried by the housing.

The cartridge may have the first and second generally planar wingscarried on the housing by a pivotal mounting dimensioned and configuredto permit movement of the first and second generally planar wings to aposition wherein the first and second generally planar wings aredisposed in parallel overlapping relationship. The cartridge may havethe first and second generally planar wings dimensioned and configuredfor passage within a slot within the associated neuromonitoring needleelectrode placement gun. The first and second generally planar wingscarried on the housing by a pivotal mounting dimensioned and configuredto permit movement thereof to a position wherein the first and secondgenerally planar wings may be disposed in parallel overlappingrelationship and the wings shield the respective pointed axialextremities to prevent either intentional or inadvertent contact withthe respective pointed axial extremity of each of the elongated needleelectrodes.

The cartridge may have the first and second generally planar wingscarried on the housing by a pivotal mounting dimensioned and configuredto permit movement of the first and second generally planar wings to aposition wherein the first and second generally planar wings aredisposed in parallel overlapping relationship. The cartridge may havethe first and second generally planar wings dimensioned and configuredfor passage within a slot within the associated neuromonitoring needleelectrode placement gun. The first and second generally planar wingscarried on the housing by a pivotal mounting dimensioned and configuredto permit movement thereof to a position wherein the first and secondgenerally planar wings may be disposed in parallel overlappingrelationship and the wings shield the respective pointed axialextremities to prevent either intentional or inadvertent contact withthe respective pointed axial extremity of each of the elongated needleelectrodes.

The first and second generally planar wings carried on the housing aremovable to a position wherein the first and second generally planarwings are substantially coplanar in some embodiments and one side ofeach of the first and second generally planar wings may be coated with areleasable adhesive suitable for simultaneous engagement with the skinof an associated patient.

The invention also includes a neuromonitoring needle electrode placementgun which includes a housing; at least a first needle electrode andhousing assembly; an elongated channel dimensioned and configured foraccommodating axial movement of the at least a first needle electrodeand housing assembly within the channel and for directing movement ofthe at least a first needle electrode and housing assembly; and a pusherdimensioned and configured for engaging the at least a first needleelectrode and housing assembly and for axially displacing the at least afirst needle electrode and housing assembly.

In some embodiments the gun further includes a plurality of needleelectrode and housing assemblies disposed in the channel. In someembodiments of the gun each needle electrode and housing assemblyincludes a needle electrode having a free end and a second end engagingthe housing. The neuromonitoring needle electrode placement gun may havea discharge axial extremity and each needle electrode and housingassembly is oriented in the channel with the free end of each needleelectrode facing the discharge axial extremity.

The neuromonitoring needle electrode placement gun in some embodimentsmay have a needle electrode and housing assembly that includes acartridge for cooperation with an associated neuromonitoring needleelectrode placement gun which includes a housing; at least one elongatedneedle electrode having an axial extent and having a pointed axialextremity carried by the housing; and at least a first generally planarwing having first and second faces thereof, the first generally planarwing being carried by the housing.

The neuromonitoring needle electrode placement gun in some embodimentsmay have a needle electrode and housing assembly that includes acartridge for cooperation with an associated neuromonitoring needleelectrode placement gun which includes a housing; at least one elongatedneedle electrode having an axial extent and having a pointed axialextremity carried by the housing; and at least a first generally planarwing having first and second faces thereof, the first generally planarwing being carried by the housing.

Each cartridge may include at least a first generally planar wing thatis coated with a releasable adhesive on the first face thereof and eachcartridge may have engagement surfaces disposed on opposed sidesthereof, the engagement surfaces being dimensioned and configured forcooperation with the elongated channel. In addition, each cartridge mayfurther include an electrically conducting wire fixed to the at leastone needle electrode for conducting either a stimulus for a patient or apatient's response to a stimulus. In addition the at least one needleelectrode may have insulation surrounding an axial portion of the axialextent of the at least one elongated needle electrode. In addition theinsulation surrounding an axial portion of the axial extent of the atleast one elongated needle electrode may be spaced a predetermineddistance from the pointed axial extremity whereby more precise resultsare achieved.

Each cartridge may further include a second elongated needle electrodehaving an axial extent and having a pointed axial extremity carried bythe housing. The free ends of each needle electrode in each cartridgemay point in the same direction and the first and second elongatedneedle electrodes may be disposed in coplanar relationship and the firstand second elongated needle electrodes in any cartridge may have therespective pointed axial extremities thereof disposed in perpendicularrelationship to and abutting a virtual line that is coplanar with thefirst and second elongated needle electrodes.

The first and second elongated needle electrodes in any cartridge may bespaced apart. Each neuromonitoring needle electrode placement gun mayhave a cartridge that includes a second generally planar wing havingfirst and second faces thereof, the second generally planar wing beingcarried by the housing. The first and second generally planar wings arecarried on the housing by a pivotal mounting dimensioned and configuredto permit movement of the first and second generally planar wings to aposition wherein the first and second generally planar wings aredisposed in parallel overlapping relationship.

The first and second generally planar wings may be dimensioned andconfigured for passage within the elongated channel. The first andsecond generally planar wings may be carried on the housing by a pivotalmounting dimensioned and configured to permit movement thereof to aposition wherein the first and second generally planar wings aredisposed in parallel overlapping relationship and the wings shield therespective pointed axial extremities to prevent either intentional orinadvertent contact with the respective pointed axial extremity of eachof the elongated needle electrodes.

The first and second generally planar wings carried on the housing maybe movable to a position wherein the first and second generally planarwings have planar surfaces thereof moveable to a position where theplanar surfaces are in abutting relationship. In some embodiments oneside of each of the first and second generally planar wings is coatedwith a releasable adhesive suitable for simultaneous engagement with theskin of an associated patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the concluding portion of thespecification. The invention, however, both as to organization andmethod of practice, together with the further objects and advantagesthereof, may best be understood by reference to the followingdescription taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of an embodiment of a neuromonitoringneedle-cartridge gun 10 assembly in accordance with one form of thepresent invention.

FIG. 2 is a front view of the assembly shown in FIG. 1.

FIG. 3 is a perspective view of an embodiment of a needle and wireassembly that is incorporated into another assembly and then utilizedwith gun assembly shown in FIG. 1.

FIG. 4 is a perspective view of an embodiment of the needle and wireassembly shown in FIG. 3 to which a needle block has been moldedresulting in a needle and wire block assembly.

FIG. 5 is another perspective view of the embodiment illustrated in FIG.4.

FIG. 6C is a side view of pivotally mounted “wings” that are attached tothe needle and wire block assembly shown in FIG. 5.

FIG. 6A and FIG. 6B are enlarged section details of the apparatus shownin FIG. 6C illustrating respectively the spring actuated rotation of thetop wing and spring loading of the top wing.

FIG. 7 is an exploded view illustrating a pair of wings that aredimensioned and configured to be snapped onto the needle block assembly.

FIG. 8 is another view further illustrating a pair of wings that areboth dimensioned and configured to be snapped onto the needle blockassembly

FIG. 9 is a partially schematic and section view illustrating theconstruction of an embodiment in which the needles are secured withinthe gun in a manner that precludes any touching of the needles afterloading the needles into the gun and immediately prior to placement in apatient.

FIG. 10 is a partially schematic view of a connection between a wirecoil, with connectors, and the needle assembly that is adhered to thepatient.

FIG. 11 is an enlarged side view of the needle assembly, shown in FIG.10, applied to a patient.

FIG. 12 shows the needle assembly after removal from the patient.

FIG. 13 is a partially broken-away side view of the overall gun 10,fully loaded with a plurality of needle and wire block assemblies thatare ready to fire for subdermal implant of the axial extremities of therespective needles in a patient.

FIG. 14 is an enlarged partially schematic view of the trigger area ofthe apparatus shown in FIG. 13.

FIG. 15A is a perspective view of a twin pusher element of the gun 10constructed to positively urge each of the respective needles in a givenneedle assembly for subdermal implant of the axial extremities of therespective needles in a patient.

FIG. 15B is a partially schematic view illustrating the manner ofengagement between the twin pusher element illustrated in FIG. 15A and agiven needle block immediately prior to subdermal implant of the axialextremities of the respective needles in a patient.

FIG. 16A and FIG. 16B are respectively side and bottom views of an axialpart of a column of needle assemblies each carrying a respective bottomwing 20 and top wing 21 permanently joined onto a ribbon thatsequentially advances respective needle assemblies.

FIG. 17 schematically illustrates the manner in which a needle assemblyis propelled fully forward and particularly illustrates a piece ofrelease paper disposed over adhesive disposed on both the top and bottomwings of a respective needle assembly.

FIG. 18 schematically illustrates the next sequential step in anembodiment of the present invention in which after the axial extremitiesof the needles are subdermal implanted and removal of the release papera small spring moves the top wing up to display an instruction to theoperator to press the wings against the skin of the patient (to avoidneedle sticks) preparatory to withdrawal of gun 10 away from the area ofthe subdermal implant.

FIG. 19 is a partially schematic representation at an initial positionof a part of the gun 10 that is simplified by representing completeneedle assemblies by needle blocks to improve clarity.

FIG. 20 is a partially schematic simplified representation similar tothat shown in FIG. 19 where the needle assemblies are advanced a partialpitch length wherein the term “pitch length” refers to the lengthbetween successive needle assemblies.

FIG. 21 is a partially schematic simplified representation similar tothat shown in FIG. 19 where the needle assemblies are advanced acomplete pitch length wherein the term “pitch length” refers to thelength between successive needle assemblies.

FIG. 22 is a partially schematic representation of the ribbon extendingbetween respective needle assemblies and having respective opposednotches at axially spaced intervals of the ribbon and particularlyshowing an axial part of the ribbon having opposed notches registeredwith a parting blade.

FIG. 23 is a partially schematic simplified representation similar tothat shown in FIG. 21 where the needle assemblies are further advancedwith the needles in the patient whereby the ribbon is axially movedforward with its needle block concurrently with an axial part of theribbon having opposed notches registered with a parting blade andthereby initiating a tear in the ribbon at the axial part of the ribbonhaving opposed notches.

FIG. 24 is a representation of the tearing of the ribbon as aconsequence of the movement illustrated in FIG. 23.

FIG. 25 illustrates a parting blade comprising a long arm with the bladeto induce parting of the ribbon at one end bent to a right angle and theother end pivotally mounted to the trigger.

FIGS. 26 and 27 are respectively vertical and horizontal sectional viewsof the front end of the gun.

FIGS. 28 and 29 are isometric views of one embodiment of the trigger.

FIG. 30 is an isometric view of an individual shelf 28 in the cassette26 illustrating a coiled extension 24 of insulated wire pair 23 disposedthereon.

FIG. 31 is a cut-away side view of an alternate embodiment, in whichneedle assemblies are pre-loaded into a magazine, which is then slid allthe way into the front end of the gun.

FIG. 32 is a scaled-up cross-section view the magazine of the alternateembodiment.

FIG. 33 is a scaled-up front-end view of magazine 72 of the alternateembodiment loaded with needle assemblies.

FIG. 34 is a top view of magazine 72 in the alternate embodiment, whichruns the full length through the gun.

FIG. 35 is an isometric view of the bottom of magazine 72 in thealternate embodiment.

DETAILED DESCRIPTION

While the invention has been described in detail herein in accordancewith certain preferred embodiments thereof, many modifications andchanges therein may be effected by those skilled in the art.Accordingly, it is intended by the appended claims to cover all suchmodifications and changes as fall within the spirit and scope of theinvention.

The apparatus and method for applying neuromonitoring needles to apatient and the means to connect to monitoring equipment are shown inFIGS. 1-30. The present invention provides a neuromonitoringneedle-cartridge gun 10 having a handle 10 a and a body 10 b best shownin FIGS. 1-2. The gun 10 cooperates with respective twin needle and wireblock assemblies 16. Each twin needle and wire block assembly 16comprises a twin needle assembly 13 with insulated wire pair 23 andconnectors 13 a as shown in FIG. 3 and FIG. 2 respectively, whichfurther includes a molded block 18 extending over a part thereof asshown in FIG. 4.

The respective needles 11 in a twin needle and wire block assembly 16are propelled into the patient with a single trigger 22 pull. In apreferred embodiment, it makes no difference if the operator holds orreleases the trigger 22 after making an initial trigger 22 pull. Aftersecuring the needles 11 (and thereby twin needle and wire block assembly16 to the patient, the gun 10 is withdrawn, whereupon a coiled extension24 of insulated wire pair 23 with connectors 13 a is extended from awire cassette 26.

FIG. 2 shows the gun 10 from a front view. The gun 10 is loaded withtwin needle and wire block assembly 16 and their associated coil oftwin-lead wire 24, with connectors. Each coil of twin-lead wire 24 hasenough wire to travel from the needle 11 placement in the patient to themonitoring equipment (not shown), where the connectors 13 a are attachedafter placement of the respective needles in the patient. The coils oftwin-lead wire 24 are stacked in a cassette 26. The cassette 26 has aplurality of parallel shelves 28. The cassette has an open front wherebyrespective coiled extension 24 of insulated wire pair 23 arerespectively dragged out of the cassette 26 after a trigger 22 pull asthe gun 10 is moved away from the patient.

Respective coiled extensions 24 of insulated wire pairs 23 withconnectors 13 a are stratified in an orderly manner, so that the topcoiled extension 24 of insulated wire pair 23 with connectors 13 a comesout of the cassette 26 first followed sequentially by the next highestcoiled extension 24 of an insulated wire pair 23. Thus, there is nocrossing or tangling of wires. The view of FIG. 2 shows twelve wirecoils 24 with connectors 13 a disposed in the gun 10. The quantity ofwire coils may be more or less in various embodiments of the presentinvention.

The needles 11 in the gun track 12 are aimed directly out the open endas shown in the left (as viewed) part of FIG. 1 as well as FIGS. 26 and27. Until the trigger 22 is actuated, the needles 11 are recessed in thetrack 12. Accordingly, the needles 11 cannot be touched eitherinadvertently or intentionally. In this embodiment, the cassette shelves28 have a “zigzag” step in which respective coiled extensions 24 ofinsulated wire pairs 23 are stacked alternately upside-down andupside-up to conserve space with connectors 13 a off to one side.Embodiments of the present invention employ such arrays to lower theoverall stack height and thereby result in a lower profile to theoverall apparatus. More specifically as shown in FIG. 2, the connectors13 a appear as two side-by-side stacks of twin connectors. Each pair ofconnectors 13 a is attached to a full-width coil of wire 24, and thewire and connector assemblies are stacked alternately, one up, one down.The uppermost coil 24 with connectors 13 a is connected to thefront-most needle and wire assembly 14 on the needle output deck 32 ofthe gun 10. Other embodiments may utilize a community mailbox like setof pigeonholes to receive respective coiled extension 24 of an insulatedwire pair 23.

FIG. 3 illustrates the construction of a twin needle assembly 13. Eachconductor of an insulated wire pair 23 is permanently joined inelectrical contact with a respective needle 11 in a twin needle assembly13. These two conductors become an insulated wire pair 23 at themidpoint between the needles 11, and extend rearward relative to needle11 direction as best seen in FIG. 3. Each needle 11 is provided with atight-fitting insulating sleeve 11 a, such as shrink tube, so thatinsulating sleeve exposes a precise length of the axial extremity ofeach needle 11 a. This is to satisfy requirements of the monitoringequipment for accuracy of nerve impulse measurements.

The twin needle and wire block assembly 16 consists of a twin needleassembly 13 and a molded block 18. A higher assembly that furtherincludes wings 20 and 21 is shown in FIG. 6C and FIG. 7.

FIG. 4 shows a molded block 18 molded over the needles and the wires.The insulated wires exit the block centrally as a “twin-wire” joinedpair (destined for the “wire cassette”). A molded block 18 spans thewidth of the track 12 in the gun 10, and pivotally supports a bottomwing 20 and a top wing 21 best seen in FIG. 7. The wings 20, 21 securethe assembly to the patient.

FIGS. 6A, 6B, 6C and FIG. 7 illustrate the relationship of pivotallymounted wings 20, 21 to the molded block 18. The upper or top wing 21 isspring loaded by a little low force wire-form spring 30 placed inboardon the pivot pin prior to snapping on the wing 21. This spring 30 urgesthe upper wing 21 to swing up to its initial installed vertical positionas shown in FIG. 6A. This movement of the upper wing 21 in response tothe bias of the spring 30 occurs after the needle assembly 14 ispropelled to the output deck 32 of the gun 10 in the customary use ofthe illustrated embodiment of the present invention. The respectivepairs of wings 20, 21 are respectively snapped on coaxial bottom pins 14a and coaxial upper pins 14 b carried by the molded block 18. The upperwing 21 retains the spring 30, as noted above. The spring 30 cannotescape from its installed position due to the loops at each end (bestseen in FIGS. 6A and 6B.), which will not fit through the cracks of thestructure. Coaxial bottom pins 14 a disposed at the opposed axialextremities of the molded block 18 extend out beyond coaxial upper pins14 b also disposed at the opposed axial extremities of the molded block18. The coaxial bottom pins 14 a ride in grooves on opposed sides of thegun track 12 in order to provide further guidance for the needle andwire assembly 14 as it advances along the track 12 in the gun 10.

The two-spaced rectangular open-ended cutouts 20 a (shown in FIG. 7) inthe lower wing 20, provide clearance for the pusher rails 34 to extendbehind a needle and wire block assembly 16 that is next to be pushed.See FIGS. 15A, 15B, 16A, and 16B.

The wings 20, 21 each have an adhesive coating, protected from exposureuntil use, by a layer of release paper that is easily pulled off by theoperator at the time of application to the patient. The top wing 21 hasthe adhesive on the broad flat top surface thereof and the bottom wing20 has the adhesive on the broad flat bottom surface thereof. Theoperator exposes the adhesive on the pivotally mounted wings 20, 21 andpresses the respective adhesive surfaces thereof to the skin of thepatient being monitored and thereby secures the assembly to the patient.

A preferred embodiment described herein contains 12 needle assemblieslined-up in the gun track 12, and corresponding 12 sets of wiresincluding connectors 13 a, tucked in a stratified manner into the wirecassette above the track 12. The needle assemblies are lined-upnose-to-tail, not counting the needles, which ride below the wing 20 ofthe preceding assembly.

As best seen in FIG. 9 the points of the needles 11 do not touchanything at any time prior to subcutaneous placement in a patient. Theneedles cannot drop to the track 12 floor because the roof of the guntrack 12 holds down the upper wing 21, and that wing 21 bears againstthe needle and wire block assembly 16 and thus prevents the needle andwire block assembly 16 from rotating downward with the needle 11.

As best seen in FIG. 10 the coil of twin-lead wire 24 is connected byconnectors 13 a to a needle and wire block assembly 16 that is adheredto the patient P. The wire coil 24, with its connectors, is dragged fromone of the respective shelves 28 in the cassette 26. The coil 24includes a long free wire upon pulling the coiled extension 24 ofinsulated wire pair 23 away from a relatively low tack adhesive patch 70that initially secures the coiled extension 24 of insulated wire pair 23to one of the shelves 28 in the cassette 26. Some of the low tackadhesive patch 70 is made to stick to one of the shelves 28 and willrelease upon the coiled extension 24 of insulated wire pair 23 beingdragged as the gun is moved away from the patient P. The main body ofadhesive faces the coil 24, and holds it neatly coiled until theoperator manually removes the low tack adhesive patch 70 from the coiledextension 24 of insulated wire pair 23. Then the full length of thepreviously coiled extension 24 of insulated wire pair falls free, readyto be drawn over to the monitoring equipment. This can be done wheneverthe operator is ready, even after all needles are attached to thepatient, and the patient is positioned as desired. The gun track 12 ofthe gun 10 is elongated. The other axial extremity of the coiledextension 24 of insulated wire pair 23 is fixed to the insulated wirepair 23 that is dimensioned to allow free movement of the needles 11through the track 12.

FIG. 11 is an enlarged view of the needle and wire block assembly 16applied to a patient. The angle of entry for the needles is determinedby the operator aiming the gun 10. The mounting of the wings 20, 21permits angular travel to any desired angular orientation about therespective mounting axis thereof and thus the adhesive surfaces thereofcan be applied to the skin of the patient. The wings 20, 21 are designedfor ease of removing the assembly from the patient. A fingernail tab 40assists in lifting the bottom wing 20 from the patient. The rest of theassembly is stripped from the patient by pulling the upper wing 21 andthe wire. The insulated wire pair 23 in a preferred embodiment isruggedized and securely mounted in the needle and wire block assembly16.

FIG. 12 shows the needle and wire block assembly 16 after removal fromthe patient. The wings 20, 21 are disposed in planar face to planar facecontact. The respective planar faces immediately stick to each otherbecause they still have the adhesive that stuck to the skin of thepatient. The needles 11 are obscured between the wings 20 and 21, andthus protected from both intentional and unintentional contact byanybody. Post-operative cleanup is now much safer than in prior artmanual procedures because there are no exposed needles 11. The ruggedinsulated wire pair 23 functions as a lanyard that can be pulled asneeded during removal.

FIG. 13 is a partially cut-away side view of the overall gun 10, fullyloaded and ready to fire. The trigger 22, also shown in FIGS. 28, 29 isa lever, which can be operated by one or more fingers. A bi-directionalanti-backup trigger pawl 42 engages a rotary ratchet 44 on the rear ofthe trigger 22 after the trigger 22 has been moved a short distance fromthe initial position. It will be understood that the rotary ratchet 44formed on a planar member is rigidly fixed to the trigger 22 and thushas the same center of rotation as the trigger 22. (In some embodiments,the rotary ratchet 44 and the rest of the trigger 22 are manufacturedfrom a single piece and that piece is metal.) Because of thebi-directional anti-backup trigger pawl 42 engagement with the rotaryratchet 44 on the rear of the trigger 22 the trigger 22 must be fullyactuated before the trigger 22 can reset back to the initial position.The trigger pawl 42 also works in the other direction, so that once thetrigger has moved away from the handle 10 a, the trigger 22 must returnto the initial position where the trigger is spaced from the handle themaximum possible distance before another firing cycle can occur. Atrigger pawl spring 43 pulls the spring-loaded bi-directional pawl 42 toits central waiting or default position. In addition, the trigger 22 hasmotion limit stop 48 to preclude over-travel.

FIG. 14 is a view of the trigger 22 area of the FIG. 13. Also shown aresimplified views of parts needle and wire block assembly 16 (justneedles and needle blocks) to illustrate how the needles 11 ride in thegun track 12 including illustrating how the points of the respectiveneedles 11 travel without interference. The respective legs of thepusher rail 34 are propelled forward when the trigger 22 is actuated.More particularly the pusher rail 34 is propelled by an elongated link50 riding on an arcuate cam ramp 52. Return force for combined pusherrail 34, elongated link 50 and trigger 22 is provided by a triggerreturn spring 55 connecting the pusher rail 34 to a fixed point 54 onthe gun 10. The trigger return spring 55 is disposed in a differentplane than the arcuate cam ramp 52 to avoid interference. The triggerreturn spring 55 also provides an upward force for the pusher rail 34,so that the pusher rail 34 will snap in behind the next-in-line needleand wire block assembly 16, upon trigger 22 return (reset) to theinitial position as shown in FIG. 13. The horizontal travel of theforward arm 56 of the trigger 22, which drives the ribbon-parting blade62 is non-linear, and stays at nearly the same horizontal location forthe last half of the trigger actuation so the parting blade remainswhere needed. This positions the blade for ribbon parting synchronizedwith the pusher displacement. The blade is cammed up with appropriatetiming, as seen later in FIGS. 19-24.

FIG. 15 shows the pusher rail 34 comprising first and second parallelelongated legs. Each leg of the pusher rail 34 extends through one ofopen-ended cutouts 20 a of the bottom wing 20 to engage a needle andwire block assembly 16. The spaced legs of the pusher rail 34simultaneously engage spaced apart lateral portions of the needle andwire block assembly 16. This arrangement insures stability of the needleand wire block assembly. FIG. 15B is a side cut-away view showing thepusher rails back at the home position, ready to propel the next-in-lineneedle and wire block assembly 16 each carrying a respective bottom wing20 and top wing 21. The push of the pusher rail 34 implants the needles11 subcutaneously in the patient as best seen in FIG. 17.

FIGS. 16A and 16B respectively illustrate a side view and a bottom viewof an axial part of a column of needle and wire block assembly 16carrying a bottom wing 20 and a top wing 21 each joined to a ribbon 36.The distance between identical points on each of two successive needleand wire block assembly 16 is the pitch of the column. The entire columnmoves one pitch length forward in the gun track 12 when the trigger 22is cycled between an initial position (as shown) to a fully depressedposition. The legs of the pusher rail 34 on the needle and wire blockassembly 16 nearest the discharge axial extremity of the track 12advances both that individual needle and wire block assembly 16 as wellas the ribbon 36 and all the other needle and wire block assemblies 16(each carrying a respective bottom wing 20 and top wing 21) attached tothe ribbon 36. The ribbon 36 is provided with a pair of opposed notches36 a at one pitch length intervals along the axial extent of the ribbon36. The wing 20 clearance cutout areas 20 a, shown in the bottom view,allow the pusher 34 legs to get behind the needle and wire blockassembly 16 nearest the discharge end of the track 12 to accuratelyadvance both that needle and wire block assembly 16 with the top andbottom wings secured thereto as well as the trailing ribbon and otherattached needle and wire block assemblies 16 with their respective topand bottom wings secured thereto.

FIG. 17 illustrates the position of a needle and wire block assembly 16propelled fully forward. A message for the gun 10 operator isautomatically presented. Each needle assembly comes with a respectivepiece of release paper extending over the adhesive on each of the topand bottom wings 20 and 21. Each such release paper overlaps theadhesive slightly to make its removal easier. The top release paper hasthe printed message illustrated in FIG. 17. This message is prominentlypresented when the needle and wire block assembly 16 is fully propelledas the result of the trigger 22 being fully actuated. Accordingly, theneedles 11 have been propelled into the patient (not shown). The releasepaper 58 extends back under the top of the gun track 12 in order toretain the position of that spring-loaded wing until the release paperin removed. Upon removal of the release paper 58, the spring 30 alsoshown in FIGS. 6A-6C swings the wing 21 upward as shown in FIG. 18.

FIG. 18 shows the next step for the operator after the step illustratedin FIG. 17. Upon removing the release paper 58, the spring 30 swings thetop wing 21 up to where the next message is prominently displayed. Aftera respective pair of needles 11 is positioned in the patient (not shown)and the operator presses the wing 21 against the skin of the patient.This secures the needle and wire block assembly 16 to the patient, andthe gun 10 is drawn away. As the gun 10 is drawn away, the wire coil 24,with connectors 13 a, comes out of the cassette 26. The operator removesthe release paper 58 from the bottom wing 20 and presses the bottom wing20 to the skin of the patient. Upon removing the adhesive patch 30 fromthe wire coil 24 and its connectors 13 a, a long length of wire isreleased to deliver the connectors 13 a to the measurement equipment(not shown).

FIGS. 19-24, show the operation inside the front of the gun 10 during afiring cycle. The ribbon 36, having a plurality of attached needle andwire block assemblies 16 each with an attached top wing 21 and bottomwing 20 is drawn forward. Thereafter, the ribbon 36 is severed so thatthe then front most needle and wire block assembly 16 each with anattached top wing 21 and bottom wing 20 attached and its associatedcoiled extension 24 of insulated wire pair 23 can exit the gun 10 whilethe ribbon with the attachments thereto is held in place. A springloaded anti-backup pawl 43 is constantly blocking the plurality ofneedle and wire block assemblies 16 that are collectively referred toherein as a column. More particularly the anti-backup pawl 38 blocks thecolumn from slipping backward. The column has enough friction withrespect to the gun track 12 so that the column will resist slippingforward. Upon the occurrence of very unusual circumstances, such asdropping the gun 10 on a hard table surface, the operator will initiatea “clearing” cycle to insure no malfunction has or will occur. Thisreturns the mechanism to a normal condition with everything back tonormal, minus one needle and wire block assembly 16 each with anattached top wing 21 and bottom wing 20 attached and its associatedcoiled extension 24 of insulated wire pair 23. The anti-backup pawl 38cooperates with a wire-form spring 66 molded into the body thereof atthe pivot for the pawl 38. The pawl 38 is biased by the spring 66. Theother end of the wire-form spring 66 is fixed on a spring anchor pin 60carried on the gun body 10 b.

FIG. 19 shows the condition of a portion of the apparatus before, or at,the start of a firing cycle. For clarity, the view is simplified e.g.,blocks 68 represent complete needle and wire block assemblies 16together with a top wing 21 and a bottom wing 20.

FIG. 20 shows a plurality of simplified blocks 68 each representingcomplete needle and wire block assemblies 16 together with a top wing 21and a bottom wing 20 advanced forward a partial pitch length. The pusherpair (not shown) is bearing on the rear most surface of the leadingcomplete needle and wire block assemblies 16 together with a top wing 21and a bottom wing 20. The column is advanced forcefully over a pawl 38(biased by pawl spring 43), which deflects downward. A ribbon-partingblade 62, also shown in FIG. 25 is starting to climb up a ribbon partingblade cam ramp 64. (Cam ramps in this gun 10 are provided with a thinfilm of silicone grease.) The parting blade 62 in a preferred embodimentis not sharp and does not cut anything. It works on an altogetherdifferent principle, illustrated in FIGS. 22, 23 and 24.

FIG. 21 shows blocks 68 representing complete needle and wire blockassemblies 16 advanced one full pitch length. The pawl 38 has sprungback up to prevent rearward slippage. The ribbon 36 is attached to theneedle and wire block assembly 16 with enough slack to allow the pawl 38to move far enough upward to, once again, provide positive anti-backupfor the train of needle assemblies. The parting blade 62 is cammed toits uppermost position. The ribbon 36 has opposed notches 36 a at axialintervals equal to the pitch of the mechanism as shown in FIGS. 16B and22). An engagement surface 62 a is now registered in the opposed notches36 a, each having an acute included angle, with a sharp apex, tofacilitate tearing of the ribbon 36. Further motion by the twin pushers(not shown) against the forward needle block starts a tearing action inthe ribbon 36 between the opposed notches 36 a. The next needle block 68cannot advance forward during the remainder of this cycle because it isup against the rigid parting blade, which will not move.

FIG. 22 shows the ribbon 36 with its opposed notches 36 a pulled up overthe engagement surface 62 a of a ribbon parting blade 62. The engagementsurface 62 a of a ribbon parting blade 62 is dull, whereas the opposednotches 36 a of the ribbon 36 have an enclosed acute angle. The nextsequential needle and wire block assemblies 16 together with a top wing21 and a bottom wing 20 with its attached ribbon 36, cannot move anyfarther because the engagement surface 62 a of the ribbon parting blade62 is in the way. Further axial pulling on the ribbon 36 by the forwardneedle block will cause a tear to start between the opposed notches 36 ain the ribbon 36. The ribbon 36 tears incrementally as the ribbonparting blade 62 and particularly the engagement surface 62 a engagesthe opposed notches 36 a so there is no sudden pop when the ribbonparts.

FIG. 23 shows the front needle assembly propelled fully forward. Theneedles are in the patient (not shown). The ribbon 36 is forced to moveforward with its needle block, and therefore forces a tear in the ribbon36 at the opposed notches 36 a parts the ribbon 36.

FIG. 24 shows the result of the action described above. The leftoverpiece of ribbon 36 simply stays with the deployed needle and wire blockassembly 16.

FIG. 25 shows the complete parting blade 62, which in the illustratedembodiment has an elongated body having a right-angle bend at one axialextremity. That axial extremity has an engagement surface 62 a. Theother axial extremity is pivotally mounted to the trigger 22. FIG. 30 isan isometric view of an individual shelf 28 in the cassette 26illustrating a coiled extension 24 of insulated wire pair 23 disposedthereon.

The wings 20 and 21 are disposed in parallel planes when the wings arein the gun. Thereafter, upon ejection from the gun the wings rotate towhatever angle is needed for each the respective wings to have planarface contact with the patient and specifically so that the respectivewings have planar face contact with the skin of the patient on each sideof a given needle electrode, and are thereafter rotated further tobecome parallel again, but 180 degrees from original, as they obscurethe needles upon removal from the patient. Thus, the wings are almostcoplanar as they rest nearly against each other, with needles obscuredbetween, and held by the adhesive thereon.

Although the above description of various preferred embodimentsemphasizes cartridges which support two parallel needle electrodes forsimultaneous subcutaneous placement in the body of a patient, it will beunderstood by those skilled in the art that other embodiments mayalternatively only implant a single needle electrode upon actuation ofthe trigger. The embodiments described above utilize a cartridge havingcylindrical surfaces disposed at respective axial extremities thereofthat engage respective parallel opposed channels in a track or slot.Other embodiments may change the gender of the coupling between therespective cartridges and the track or slot in which the cartridgesmove. For example, the respective cylindrical surfaces of each cartridgemay have a slot that is dimensioned and configured for engagingrespective rails on opposed sides of the track or slot.

The language used in the claims and specification to describe theapparatus of the present invention may use terms such as “barrel” and“magazine” to describe embodiments of the present invention because theterms facilitate description of the apparatus despite some materialdifferences between the apparatus of the present invention and thetypical apparatus in the firearms field where the term “barrel” usuallyrefers to an elongated cylindrical element and the term “magazine”usually refers to a mechanism for holding a plurality of cartridges orshells. As used herein the term “barrel” refers to an elongatedstructure that directs one or more needle electrodes toward a patient.As used herein the term “magazine” refers to a structure for holding oneor more needle electrode assemblies and intended for subsequentsequential placement in a patient.

In those embodiments of the present invention in which the sterilepreloaded gun is sealed in a blister pack, the gun may be loaded with afixture (not shown) that holds a plurality needle electrode assembliesin a rectilinear array aligned with the barrel. Other embodiments of thepresent invention utilize a magazine sleeve having an arcuate crosssection holding a plurality of needle electrode assemblies whereby theloaded magazine may be inserted in the barrel of the assembly insubstantially concentric relationship.

FIG. 31-FIG. 35 illustrate an alternate embodiment of the presentinvention. FIG. 31 is a cut-away side view of the alternate embodiment,in which needle assemblies are pre-loaded into a magazine, which is thenslid all the way into the front end of the gun. The magazine 72 is fullyinserted into the gun body 10 b. The inside of the tubular magazinebecomes the track 12, along which, the needle assemblies, not shown, arecarried. The output deck 32, anti-backup pawl 38, ribbon parting blade62, pusher rail(s) 34, and the rest of the gun body 10 b remain exactlythe same as the previously described embodiment.

FIG. 32 is a scaled-up cross-section view of the magazine 72. FIG. 33 isa scaled-up front-end view of the magazine 72 loaded with needleassemblies. The viewer sees needle and wire block assembly 16, top wing21, ribbon 36, and needle(s) 11. FIG. 34 is a top view of the magazine72, which runs full length through the gun. Slot 72 a (full length)accommodates the wire(s) 23 (still used, but not shown in this figure)of the previously described embodiment. Cutout 72 b accommodates thepusher rail(s) 34 (still used, but not shown in this figure).

FIG. 35 is an isometric view of the bottom of the magazine 72. It moreplainly shows the cutout 72 b, which allows the pusher rail(s) 34, notshown, to get behind, and then push, the front-most needle assembly, notshown in this figure.

All publications and patent applications mentioned in this specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The previous description is provided to enable any person skilled in theart to practice the various embodiments described herein. Variousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other embodiments. Although the description above containsmany specifics, these should not be construed as limiting the scope ofthe invention, but as merely providing illustrations of some of thepresently preferred embodiments of this invention. Thus, the claims arenot intended to be limited to the embodiments shown herein, but is to beaccorded the full scope consistent with the language claims, whereinreference to an element in the singular is not intended to mean “one andonly one” unless specifically so stated, but rather “one or more.”Therefore, it will be appreciated that the scope of the presentinvention fully encompasses other embodiments which may become obviousto those skilled in the art, and that the scope of the present inventionis accordingly to be limited by the appended claims, in which referenceto an element in the singular is not intended to mean “one and only one”unless explicitly so stated, but rather “one or more.” Furthermore, itshould be understood that while the use of the word preferable,preferably, or preferred in the description above indicates that featureso described may be more desirable, it nonetheless may not be necessaryand any embodiment lacking the same may be contemplated as within thescope of the invention, that scope being defined by the claims thatfollow. In reading the claims it is intended that when words such as“a,” “an,” “at least one” and “at least a portion” are used, there is nointention to limit the claim to only one item unless specifically statedto the contrary in the claim. Further, when the language “at least aportion” and/or “a portion” is used the item may include a portionand/or the entire item unless specifically stated to the contrary. Allstructural, chemical, and functional equivalents to the elements of theabove-described preferred embodiment that are known to those of ordinaryskill in the art are expressly incorporated herein by reference and areintended to be encompassed by the present claims. Moreover, it is notnecessary for a device or method to address each and every problemsought to be solved by the present invention, for it to be encompassedby the present claims. Furthermore, no element, component, or methodstep in the present disclosure is intended to be dedicated to the publicregardless of whether the element, component, or method step isexplicitly recited in the claims. No claim element herein is to beconstrued under the provisions of 35 U.S.C. 112, sixth paragraph, unlessthe element is expressly recited using the phrase “means for.”

What is claimed is:
 1. A method which comprises: monitoring myogenicactivity selected from the group consisting of spontaneous andelectrically evoked myogenic activity in a patient by sequentialplacement of a plurality of first and second needle electrodes disposedin coplanar, uniformly spaced apart and parallel relationship with freeends thereof abutting a virtual line that is perpendicular to the firstand second needle electrodes; providing a plurality of respective needleand housing assemblies each including a body supporting respective firstand second needle electrodes providing an elongated rectilinear trackdimensioned and configured for receiving and allowing axial slidingmovement of respective needle and housinq assemblies and having a freeend allowing passage of free ends of the first and second needleelectrodes out of the free end of the track whereby the needleelectrodes are subdermal electrodes, the free ends of the first andsecond needle electrodes shallowly placed in the patient; positioningthe free end of the track in oblique relationship the skin of a patient;and providing a mechanism for selectively engaging respective axiallyspaced needle and housing assemblies along at least a part of the axialextent of the track as well as out of a discharge end of the track toengage each needle in respective needle and housing assembliessubcutaneously into a patient.
 2. The method as described in claim 1further including providing pivotally mounted wings carried onrespective needle and housing assemblies which shield respective pointedaxial extremities to prevent either intentional or inadvertent contactwith the respective pointed axial extremities of the needle electrodes.3. the method as described in claim 2 wherein the step of providingpivotally mounted wings includes providing pivotally mounted wings thathave a releasable adhesive thereon.
 4. The method as described in claim3 further including providing a ribbon joining successive needle andhousing assemblies.
 5. The method as described in claim 4 furtherincluding providing a ribbon parting apparatus for selectivelyseparating an individual needle and housing assembly.
 6. The method asdescribed in claim 1 wherein the step of providing the mechanismincludes providing a member that provides reciprocal movement to engagean individual needle and housing assembly nearest the discharge end ofthe track.